Methods for treating tobacco material, apparatus for treating tobacco material, treated tobacco material and uses thereof

ABSTRACT

A method of treating tobacco material including combining pre-cut and/or pre-expanded stem with lamina to form an initial combination of stem and lamina; cutting the initial combination of stem and lamina; expanding the combination of stem and lamina; and intermittently contacting the expanded combination of stem and lamina with a heated surface to produce a treated tobacco material. An apparatus is also provided for treating tobacco material. Also provided is a treated tobacco material, as well as products including the same.

PRIORITY CLAIM

The present application is a National Phase entry of PCT Application No. PCT/GB2021/050481, filed Feb. 25, 2021, which claims priority from GB Application No. 2002790.0, filed Feb. 27, 2020, each of which is hereby fully incorporated herein by reference.

TECHNICAL FIELD

The present invention provides a method of treating tobacco material. Also provided is an apparatus for treating tobacco material. The invention also provides treated tobacco material, as well as products comprising the same.

BACKGROUND

Various processes and apparatus are known for expanding tobacco material in order to improve the fill value of the tobacco material.

SUMMARY

According to a first aspect of the invention, a method of treating tobacco material is provided comprising: combining pre-cut and/or pre-expanded stem with lamina to form an initial combination of stem and lamina; cutting the initial combination of stem and lamina; expanding the combination of stem and lamina; and intermittently contacting the expanded combination of stem and lamina with a heated surface to produce a treated tobacco material.

In some embodiments, the initial combination of stem and lamina comprises from at least about 5% lamina up to about 99% lamina, by weight, and/or from at least about 1% stem up to about 95% stem, by weight.

In some embodiments, the expanded combination of stem and lamina is agitated so that it is intermittently in contact with the heated surface.

In some embodiments, the heated surface has a temperature of from at least about 100° C. to about 300° C. prior to contact with the tobacco material.

In some embodiments, the heated surface has a temperature of from at least about 120° C. to about 250° C. prior to contact with the tobacco material, or from at least about 150° C. to about 300° C. prior to contact with the tobacco material.

In some embodiments contacting the expanded combination of stem and lamina with the heated surface heats the tobacco material to a peak temperature of from about 120° C. to about 230° C.

In some embodiments, the heated surface is a heated metal surface.

In some embodiments, the treated tobacco material has a moisture content from 0 to about 10% oven volatiles (OV),

In some embodiments, the expanded combination of stem and lamina has a moisture content of at least 5% OV before it is intermittently contacted with a heated surface. In some embodiments, the expanded combination of stem and lamina has a moisture content of from about 5% to about 25% OV before it is intermittently contacted with a heated surface, or from about 12 to about 16% OV.

In some embodiments, the expanded combination of stem and lamina is intermittently contacted with a heated surface for a period of from at least about 1 minute to about 15 minutes. In some embodiments, the expanded combination of stem and lamina is intermittently contacted with a heated surface for a period of from at least about 2 minutes to about 10 minutes. In some embodiments, the expanded combination of stem and lamina is intermittently contacted with a heated surface for a period of from at least about two and a half minutes to about 5 minutes.

In some embodiments, at least one of water and steam is added to the expanded combination of stem and lamina whilst it is intermittently contacted with a heated surface, to increase its moisture content. In some embodiments, at least one of water and steam is repeatedly added to the expanded combination of stem and lamina whilst it is intermittently contacted with a heated surface, to increase its moisture content.

In some embodiments, the method is a continuous process.

In some embodiments, the expanded combination of stem and lamina is agitated by at least one of the group consisting of: a screw mechanism; a dual screw mechanism; airflow; and a rotating drum.

In some embodiments, the fill value of the treated tobacco is at least about 5% or at least about 15% greater than the fill value of the combination of stem and lamina immediately prior to the step of intermittently contacting the expanded combination of stem and lamina with a heated surface. In some embodiments, the fill value of the treated tobacco is from about 30% to about 50% greater than the fill value of the initial combination of stem and lamina.

In some embodiments, the sugar content of the treated tobacco is from about 20% to about 95% less than the sugar content of the initial combination of stem and lamina. In some embodiments, the sugar content of the treated tobacco is from about 60% to about 90% less than the sugar content of the initial combination of stem and lamina.

In some embodiments, the nicotine content of the treated tobacco is from about 10% to about 80% less that the nicotine content of the initial combination of stem and lamina. In some embodiments, the nicotine content of the treated tobacco is from about 35% to about 70% less that the nicotine content of the initial combination of stem and lamina.

In some embodiments, the ammonia content of the treated tobacco is from about 30% to about 99% less that the ammonia content of the initial combination of stem and lamina. In some embodiments, the ammonia content of the treated tobacco is from about 50% to about 90% less that the ammonia content of the initial combination of stem and lamina.

In some embodiments, the cut combination of stem and lamina is expanded by exposing the cut stem and lamina to an expansion agent. In some embodiments, the expansion agent is selected from the group consisting of: liquid carbon dioxide, solid carbon dioxide, steam, liquid nitrogen, liquid short (C5 or C6) chain carbohydrates, or mixtures thereof.

According to a second aspect of the invention, an apparatus for carrying out a method according to the first aspect is provided, the apparatus comprising a module for intermittently contacting the expanded combination of stem and lamina with a heated surface, the module comprising a heated surface provided to intermittently contact the expanded combination of stem and lamina.

In some embodiments, the apparatus comprises a means for agitating the expanded combination of stem and lamina. In some embodiments, the means for agitating the expanded combination of stem and lamina comprises at least one of the group consisting of: a screw mechanism; a dual screw mechanism; airflow; and a rotating drum.

In some embodiments, the heated surface has a temperature of from at least about 100° C. to about 300° C. prior to contact with the tobacco material. In some embodiments, the heated surface has a temperature of from at least about 120° C. to about 250° C. prior to contact with the expanded combination of stem and lamina, or from at least about 150° C. to about 300° C. prior to contact with the expanded combination of stem and lamina.

In some embodiments contacting the expanded combination of stem and lamina with the heated surface heats the expanded combination of stem and lamina to a peak temperature of from about 120° C. to about 230° C.

In some embodiments, the heated surface is a heated metal surface. In some embodiments, the heated surface is heated by a heating medium, the heating medium being water, oil, steam, electricity, or combinations thereof.

According to a third aspect of the invention, a treated tobacco material is provided, which is obtained or obtainable by a method according to the first aspect.

In some embodiments, the treated tobacco material has reduced levels of one or more of the group consisting of: sugars, nicotine and ammonia, compared to level in the initial combination of stem and lamina.

In some embodiments, the sugar content of the treated tobacco is from about 20% to about 95%, or from about 60% to about 90%, less than the sugar content of the initial combination of stem and lamina.

In some embodiments, the nicotine content of the treated tobacco material is from about 10% to about 80%, or from about 35% to about 70%, less than the nicotine content of the initial combination of stem and lamina.

In some embodiments, the ammonia content of the treated tobacco material is from about 30% to about 99%, or from about 50% to about 90%, less than the ammonia content of the initial combination of stem and lamina.

In some embodiments, the fill value of the treated tobacco is at least about 25% or at least about 30% greater than the fill value of the initial combination of stem and lamina. In some embodiments, the fill value of the treated tobacco is from about 30% to about 50% than the fill value of the initial combination of stem and lamina.

According to a fourth aspect of the invention, a tobacco industry product is provided comprising the treated tobacco material according to the third aspect.

According to a fifth aspect of the invention, the use of the treated tobacco material according to the third aspect is provided, for the manufacture of a tobacco industry product.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 shows a process flow chart of an exemplary method; and

FIG. 2 is a schematic illustration of the progress of the tobacco material through an apparatus for treating tobacco material.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention seeks to improve the processing of tobacco material in preparation for its incorporation into a tobacco industry product. As discussed below, tobacco industry products include smoking articles such as combustible cigarettes, as well as tobacco heating products and the like. Tobacco industry products also include non-smoking products incorporating tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes.

After harvesting, tobacco material can be treated in various ways to prepare the material for consumption. One treatment is drying. The purpose of drying is to remove moisture from the tobacco material. Another treatment is expansion of the tobacco material. The purpose of expansion is to increase the fill value of the tobacco. A yet further treatment or series of treatments may have the purpose of improving the organoleptic and/or taste characteristics of the tobacco material.

The present invention seeks to achieve all of these effects in a simple and relatively fast process, whilst also producing a treated tobacco material that is has a high consistency or uniformity in terms of color, particle size and combustion properties, despite the starting material comprising both stem and lamina.

As used herein, the term “tobacco material” includes any part and any related by-product, such as for example the leaves or stems, of any member of the genus Nicotiana. The tobacco material for use in the present invention is preferably from the species Nicotiana tabacum.

Any type, style and/or variety of tobacco may be treated. Examples of tobacco, which may be used, include, but are not limited to, Virginia, Burley, Oriental, Comum, Amarelinho and Maryland tobaccos, and blends of any of these types. The skilled person will be aware that the treatment of different types, styles and/or varieties will result in tobacco with different organoleptic properties.

The tobacco material may be pre-treated according to known practices.

The tobacco material to be treated may comprise and/or consist of post-curing tobacco. As used herein, the term ‘post-curing tobacco’ refers to tobacco that has been cured but has not undergone any further treatment process to alter the taste and/or aroma of the tobacco material. The post-curing tobacco may have been blended with other styles, varieties and/or types. Post-curing tobacco does not comprise or consist of cut rag tobacco.

Cigarettes typically contain blends of different types of tobaccos. Three main types of tobacco are commonly used in these blends, namely Virginia, Burley and Oriental. These main tobacco types are further distinguished into subgroups depending upon where the tobacco is grown, which part of the plant it is taken from, and other characteristics that relate to the perceived quality of the tobacco, including color, maturity, and uniformity. Different types and different subgroups have different properties. The three main tobacco types and the subgroups may have different taste characteristics and differing nicotine content.

Whole tobacco leaves contain a central stem (or midrib) and the leaf (lamina). These parts of the leaves are typically separated by mechanical threshing.

Threshing and classification is repeated until all of the stem and lamina are separated. They are then processed separately. The stem typically undergoes conditioning to give the stem a higher moisture content than the green leaf. The stem is then cut, before being dried.

Following threshing and classification, the moisture content of the lamina will often vary and it is important to treat the lamina to ensure that the moisture content is uniform. First, the lamina is dried and then cooled. Next, it passes into a high humidity-conditioning chamber where the lamina absorbs moisture and reaches equilibrium. The lamina is then packaged and placed into storage until being used.

The physical characteristics of the lamina and stem vary considerably. The lamina is a more fragile structure whilst tobacco stem is more fibrous, woody and robust.

It is often desirable to include in a blend both lamina and stem in a blend for incorporation into a smoking article. Typically, these materials will be separately treated, following on from the separation and pre-treatment discussed above, before being blended for inclusion in a smoking article.

Further treatment of the lamina will involve cutting. Stem is often treated to afford it physical characteristics that resemble those of lamina more. Such treatment will often involve rolling, cutting and/or expansion.

Nevertheless, it is often the case that when smoking material comprising a blend of lamina and stem is viewed, the stem component can be discerned visually. The stem component can also provide the smoke formed upon combustion of the smoking material with a harsher and more irritant quality, compared to smoking material consisting solely of lamina.

Combining Stem and Lamina

According to the first step of the method of treating tobacco material, tobacco stem and tobacco lamina are combined. Herein, the combination of the stem and lamina formed by this step is referred to, for convenience and clarity, as the “initial combination of stem and lamina”.

The stem has already been cut and/or it has already been expanded before it is combined with the lamina.

In some embodiments, the stem has been conventionally processed before being combined with the lamina. In some embodiments, the stem has a moisture content of from about 18% to about 45% OV.

Unless stated otherwise, references to moisture content herein are references to oven volatiles (OV). Volatiles are defined as the percentage of volatile components contained in the total mass of a solid substance. This includes water and all other volatile compounds. Oven volatiles are the mass of volatile substances that were driven off. Moisture content (OV) may be measured as the reduction in mass when a sample is dried in a forced draft oven at a temperature regulated to 110° C.±1° C. for three hours ±0.5 minutes. After drying, the sample is cooled in a desiccator to room temperature for approximately 30 minutes, to allow the sample to cool.

Where the stem has been pre-cut, it has, in some embodiments, been cut to widths that range from 0.08 to 0.3 mm.

Where the stem has been pre-expanded, the expansion may be achieved by any conventional expansion step. Conventional stem expansion techniques include, for example,

Steam Treated Stem (STS) process, steaming tunnel, shredded stem process, and the process generally called cut-rolled-expanded-stem (CRES).

The lamina has been conventionally processed, covering all known processes and principles common in the tobacco industry. In some embodiments, the lamina has been conditioned and has a moisture content of from about 20% to about 30% OV. The lamina may also have been blended and may already have been treated with casing.

In some embodiments, once the stem and lamina have been combined, they may be mixed or blended to form a relatively homogenous mixture.

In some embodiments, the combination of stem and lamina may comprise from at least about 5% lamina up to about 99% lamina, and/or from at least about 1% stem up to about 95% stem. In some embodiments, the combination of stem and lamina comprises from about 5% stem and 95% lamina to about 50% stem and 50% lamina.

In some embodiments, the combination of stem and lamina further comprises reconstituted tobacco material. Reconstituted tobacco is frequently processed together with the leaf grades, and hence it may be processed with the stem and lamina in accordance with the present invention.

Cutting the Combination of System and Lamina

According to a further step of the method of treating tobacco material, the initial combination of stem and lamina is cut.

The cutting may be carried out using any conventional cutting process and/or apparatus.

In some embodiments, the initial combination of stem and lamina is cut to widths of at least about 0.2 mm. In some embodiments, the combination is cut to a width of up to about 2 mm. Normally, lamina is cut to widths of 0.6 mm to 1.1 mm for use in combustible smoking articles (for roll-your-own cigarette tobacco, significantly finer cut lamina is used, even down to a width of 0.25 mm) and stem is cut to widths of between 0.12 mm and 0.25 mm. The wider the cut the more robust the resulting product, hence the likelihood for surviving the subsequent processing steps with an acceptable particle size. However, fewer particles are produced with wider cut widths. As this process is partly, beside taste, driven by fill value of the final product, the ideal combination of particle size has to be determined. The present invention may offer the possibility to go outside the conventional window of cut widths for lamina, with widths of up to 2 mm, providing potentially even greater increases the resulting fill values of the tobacco.

Expanding the Combination of Stem and Lamina

According to a further step of the method of treating tobacco material, the combination of stem and lamina is expanded.

Cut tobacco can be expanded to reduce the mass of tobacco included and combusted in a cigarette. Many tobacco brands with low ISO tar yields will use some proportion of expanded tobacco in the overall blend.

In methods according to the present invention, the cut combination of stem and lamina is treated by an expansion step which expands the cut stem and cut lamina. In some embodiments, this expansion produces an expanded material having a fill value at least about 10% greater than the fill value of the pre-expansion cut combination of stem and lamina when measured at a normalized moisture content of 14.5% OV.

In some embodiments, the expansion step starts with the cut combination of stem and lamina which has a moisture content of from about 20% to about 40% OV prior to the expansion step.

In some embodiments, the expansion step starts with the cut combination of stem and lamina, which has a fill value of from about 3.5 to about 7 ml/g prior to the expansion step when measured at a normalized moisture content of 14.5% OV.

In some embodiments, the expansion step utilizes conventional expansion techniques. Various methods have been proposed for expanding tobacco, including the impregnation of tobacco with a gas or steam under pressure and the subsequent release of the pressure, whereby the gas causes expansion of the tobacco cells to increase the volume of the treated tobacco. This may involve the use of known lamina expansion techniques, such as: the expansion process used to produce dry-ice expanded tobacco (DIET), Flash Tower Drying, the INCOM (inert gas compression) process, and the IMPEX process that involves impregnating the tobacco with a hydrocarbon solvent and steaming tunnel in combination with a drying technique.

In some embodiments, the methods include the impregnation of tobacco with a liquid, such as water or relatively volatile organic liquids, after which the liquid is driven off to expand the tobacco. A widespread conventional expansion technique involves the use of dry ice, resulting in so-call dry-ice expanded tobacco or DIET. The process involves permeating the tobacco with liquid carbon dioxide before warming. The resulting carbon dioxide gas forces the tobacco to expand.

Other methods that may be used include the treatment of tobacco with solid materials which, when heated, decompose to produce gases which serve to expand the tobacco. Other methods include the treatment of tobacco with gas-containing liquids, such as carbon dioxide-containing water, under pressure to impregnate the tobacco with the liquid. The impregnated tobacco is then heated or the pressure reduced to cause release of the gas and expansion of the tobacco. Additional techniques have been developed for expanding tobacco which involve the treatment of tobacco with gases which react to form solid chemical reaction products within the tobacco, for example carbon dioxide and ammonia to form ammonium carbonate. These solid reaction products may subsequently be decomposed by heat to produce gases within the tobacco, which cause expansion of the tobacco upon their release. Tobacco may also be expanded by utilizing various types of heat treatment or microwave energy. Freeze-drying of tobacco can also be employed to obtain an increase in volume. Consecutive drying techniques may also be used to expand the cut combination of stem and lamina, such as air drying, and fluidized bed drying, etc.

In some embodiments, the expansion step comprises exposing the cut combination of stem and lamina to an expansion agent. The expansion agent may be selected from the group consisting of: liquid carbon dioxide, solid carbon dioxide, steam, liquid nitrogen, liquid short (C5 or C6) chain carbohydrates, or mixtures thereof.

In some embodiments, the expanded combination of stem and lamina is dry ice expanded tobacco (DIET).

It is known that such conventional expansion techniques can result in an increase in the fill value of at least about 10%. Following an expansion step using one of the aforementioned conventional expansion techniques, the cut combination of stem and lamina may have an expanded fill value of from at least about 4 ml/g (referring to the infeed fill value of 3.5 ml/g) to at least about 8 ml/g (referring to the infeed fill value of 7 ml/g) when measured at a normalized moisture content of 14.5% OV. These figures for expansion are on the conservative side and represent the minimum expansion effects of known, conventional expansion and drying processes. In reality, the expansion effects of known expansion techniques can potentially be more pronounced. For example, the expanded combination of stem and lamina may have a fill value of from about 5 ml/g to about 10 ml/g, such as from about 5 ml/g to about 9 ml/g, such as from about 5 ml/g to about 8 ml/g, such as from about 5 ml/g to about 7 ml/g when measured at a normalized moisture content of 14.5% OV.

In some embodiments, the expansion step expands the cut combination of stem and lamina to provide expanded tobacco material having a fill value at least about 12%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or at least about 100% greater than the fill value of the pre-expansion cut combination of stem and lamina when measured at a normalized moisture content of 14.5% OV.

In some embodiments, the moisture content of the expanded combination of stem and lamina is from about 5% to about 25% OV, such as from about 5% to about 20% OV, such as from about 10% to about 15% OV.

Intermittent Contact with a Heated Surface

According to a further step of the method of treating tobacco material, the combination of stem and lamina is intermittently contacted with a heated surface to produce a treated tobacco material.

It has been found that the exposure of tobacco to a hot surface not only dries the material to very low levels of moisture content (based in oven volatiles), but in some embodiments, the methods may lead to one or more of the following desirable chemical or physical changes:

-   -   a significantly improved sensorial performance of the processed         material;     -   a significantly reduced level of sugars, for example between 20%         and 90% reduction for treated cut stem and treated cut lamina;     -   a significantly reduced level of nicotine, for example between         10% and 70% reduction for treated cut stem and treated cut         lamina;     -   a significantly decreased analytical value for ammonia, for         example between 20% and 90% reduction for treated cut stem and         treated cut lamina; and     -   a significantly increased fill value, for example between 15%         and 50% increase for the processed material.

The step of intermittently contacting the combination of stem and lamina with a heated surface leads to chemical changes in the tobacco material. In at least some embodiments, these changes provide the treated tobacco material with improved organoleptic properties.

The organoleptic properties of tobacco material are conventionally enhanced by means of a variety of different treatments. Tobacco material can be cured to prepare the leaf for consumption. The tobacco material may be further treated, for example by aging or fermentation, to enhance the organoleptic properties of the tobacco. However, these processes can be lengthy and the quality of the resulting tobacco material can be variable. Treatments to enhance or add flavors and aromas to the tobacco material at a later stage of tobacco processing often involve the addition of one or more additives to the tobacco and can require additional processing steps and equipment, which can be costly and time-consuming.

The intermittent contact of the combination of stem and lamina with the heated surface results in a repetitive short-term exposure to intense heat. In some embodiments, this intermittent contact may be achieved by agitating the tobacco. The temperature of the heated surface, and thus the temperature to which the tobacco is exposed, is significantly higher than about 100° C., and, in some embodiments, is at least about 150° C. Therefore, the intermittent contact is important in order to ensure that the tobacco is not burnt as a result of prolonged continuous exposure to surfaces at such high temperatures.

In some embodiments, the intermittent contact of the tobacco with the heated surface results in the tobacco material being seared or scorched. This is as a result of the exposure to a sudden and intense heat. This has a drying effect but also results in a treatment of the tobacco that is different to the gentle drying processes known in the prior art.

In some embodiments, the oxygen levels surrounding the tobacco during treatment may be reduced. This may have the effect of reducing the risk of ‘hot spots’ forming as a result of the exposure to the heated surface, and to reduce the risk of the tobacco burning. Such reduction in the oxygen level can therefore allow the tobacco to be treated at higher temperatures than in the prior art processes and apparatus. In some embodiments, the oxygen level is reduced by the application of steam.

Without wishing to be bound by any particular theory or theories, it is hypothesized that the process can be split into two phases. During the first phase, the tobacco material is being dried as a result of the exposure to the heat, which drives off volatile components, including water, in a kind of steam distillation of the tobacco material. During the second phase, an effect which is referred to herein as “searing” occurs. It is during this second phase that the main chemical changes in the tobacco appear to occur.

It is hypothesized that the brief contact of the tobacco material with the heated surface, and the local searing of the tobacco, may lead to an increase in the products of the Maillard and carmelization reactions, many of which are known to contribute to desirable organoleptic properties. The Maillard reaction is a chemical reaction between amino acids and sugars, and these are present in the tobacco starting material, but are seen in reduced quantities in the treated tobacco material. It is a non-enzymatic reaction, which typically occurs at temperatures of from about 140 to 165° C. In addition to the pleasing effects of the Maillard reaction products on the organoleptic properties, the reaction is also responsible for the browning of materials. It has been observed that the tobacco treated in accordance with embodiments of the present invention has a darker brown color than the tobacco starting material.

In some embodiments, the treating of tobacco material by intermittently contacting it with a heated surface as described herein affords the tobacco material with an enhanced flavor profile or enhanced organoleptic properties (compared to the flavor profile of tobacco which has not been treated or which has been treated using only conventional tobacco processing). This means that there is a reduction in off-notes or irritants, whilst retaining the taste characteristics of the tobacco as would be seen following conventional tobacco processing. As used herein, the terms “enhance” or “enhancement” are used in the context of the flavor or organoleptic properties to mean that there is an improvement or refinement in the taste or in the quality of the taste, as identified by expert smokers. This may, but does not necessarily, include a strengthening of the taste.

Reference made herein to the organoleptic properties of the tobacco material may be reference to the organoleptic properties of the tobacco material itself, for example when used orally by a consumer. Additionally, or alternatively, the reference is to the organoleptic properties of smoke produced by combusting the tobacco material, or of vapor produced by heating the tobacco material. In some embodiments, the treated tobacco material affords a tobacco product including said tobacco material with desirable organoleptic properties when said product is used or consumed.

In some embodiments, the methods of the present invention have the unexpected advantage of mitigating the negative sensorial effects of stem to the overall performance of a blend. The mouth coating, cellulosic and ‘stemmy’ taste contribution is seen to be a downside of the overall stem characteristics.

It is further hypothesized that the searing also has a physical effect on the tobacco material, causing individual cells within the plant material to expand as the moisture inside them is rapidly heated and evaporates.

In some embodiments, the temperature of the heated surface is in the range of from about 100 ° C. to about 300° C. In some embodiments the temperature is at least about 105° C., 110° C., 115° C., 120° C., 125° C., 130° C., 135° C., 140° C., 145° C., 150° C., 155° C., 160° C., 165° C., 170° C., 175° C., 180° C., 185° C., 190° C., 195° C. or at least about 200° C. In some embodiments the temperature of the heated surface is up to about 295° C., 290° C., 285° C., 280° C., 275° C., 270° C., 265° C., 260° C., 255° C., 250° C., 245° C., 240° C., 235° C., 230° C., 225° C., 220° C., 215° C., 210° C., 205° C. or up to about 200° C. In some embodiments, the heated surface has a temperature of from at least about 120° C. to about 250° C., or from at least about 150° C. to about 300° C.

When discussing the temperature of the heated surface, reference is made herein to the temperature prior to contact with the tobacco material. This is because the contact with the tobacco material and the drying process can lead to cooling of the heated surface. Therefore, the exact temperature of the heated surface during the drying process will depend on how much “drying work” is done. For example, in the initial stages where water is being evaporated from the tobacco, a greater amount of energy will be utilized, thus leading to greater cooling of the heated surface.

It is therefore the temperature of the heated surface prior to contact with the tobacco that can be readily and accurately determined.

In some embodiments, the temperature of the heated surface is controlled to minimize significant changes during the treatment process. For example, a feedback mechanism may be used to ensure that the temperature is maintained within an acceptable range, heating the surface when the temperature drops as a result of the treatment of tobacco material.

In some embodiments, it is appropriate to adjust the temperature of the heated surface according to the type of tobacco material being treated. One reason why this is appropriate is that the different tobacco materials have different starting moisture contents and so treatment will involve removing different amounts of moisture and volatiles.

In some embodiments, the heated surface is metal, such as stainless steel, or any other appropriate steel and metal types with sufficient heat transfer characteristics. In other embodiments, the heated surface is made from any material with sufficient heat transfer characteristics that can be heated to the temperatures used in the methods described herein. For example, ceramic surfaces may be used.

The heated surface may, for example, be heated indirectly by a heating medium, such as a heating medium selected from the group consisting of oils, water or steam. In some embodiments, thermal oils are the preferred heating medium. Alternatively or in addition, the heated surface may be heated directly. In some embodiments, the heated surface is heated by electricity.

When the tobacco material is intermittently and repeatedly contacted with the heated surface, this will heat the tobacco material. Given the high temperatures of the heated surface, the temperature of the tobacco is raised significantly. In some embodiments, as a result of the treatment method, the temperature of the tobacco material is raised to a peak temperature in the range of from about 120 ° C. to about 230° C. In some embodiments the peak temperature of the tobacco material is at least about 125° C., 130° C., 135° C., 140° C., 145° C., 150° C., 155° C., 160° C., 165° C., 170° C., 175° C., 180° C., 185° C., 190° C., 195° C., 200° C., 205° C., 210° C., 215° C. or at least about 220° C. In some embodiments the peak temperature of the tobacco is up to about 225° C., 220° C., 215° C., 210° C., 195° C., 190° C., 185° C., 180° C., 175° C., 170° C., 165° C., 160° C., 155° C., 150° C., 145° C., 140° C., 135° C., 130° C. or up to about 125° C. The temperature of the tobacco may be measured with suitable measurement devices, such as infrared measurement or electrical resistance thermometers.

In some embodiments, the tobacco material is heated under an inert atmosphere.

In some embodiments, an inert gas, such as nitrogen, saturated steam, carbon dioxide or mixtures thereof, is added in the apparatus to control the oxygen level and thereby steer desired chemical reaction during processing.

In some embodiments, the intermittent contacting of the tobacco material with a heated surface has a drying effect and the moisture content of said tobacco material is reduced. In some embodiments, the treated tobacco material has a moisture content of from 0% to about 10% oven volatiles (OV). In other words, the treated tobacco material has a moisture content of no greater than about 10% OV. In some embodiments, the moisture content of the treated tobacco material is no greater than 9.5%, 9%, 8.5%, 8%, 7.5%, 7%, 6.5%, 6%, 5.5%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1% or no greater than about 0.5% OV. In some embodiments, the treated tobacco material has a moisture content of no greater than about 2% OV.

In some embodiments, the tobacco material has a moisture content of at least about 5% OV immediately prior to the step of intermittent contacting it with a heated surface. In some embodiments, the moisture content of the tobacco material immediately prior to this step is at least about 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, or at least about 24% OV. In some embodiments, the moisture content of the tobacco material immediately prior to this step is no greater than about 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, or no greater than about 6% OV. In some embodiments, the moisture content of the tobacco material immediately prior to this step is from at least about 5% to about 25% OV, or from at least about 5% to about 20% OV. In some embodiments, the moisture content of the tobacco material immediately prior to this step is from at least about 12% to about 16% OV.

Thus, in some embodiments, the tobacco material that is treated by intermittent contact with a heated surface has an initial moisture content that means that the tobacco material is already dried. In some embodiments, the primary purpose of the treatment of this tobacco by intermittent contact with a heated surface is not to further reduce the moisture content of the tobacco material, but to achieve the physical and chemical changes to the tobacco caused by the searing resulting from the brief contact with the high temperature of the heated surface. In some embodiments, this effect is achieved without burning or substantially without burning the tobacco material as a result of the contact with the heated surface.

In some embodiments, the moisture content of the tobacco material may be adjusted during the step of intermittently contacting the tobacco material with a heated surface by adding moisture. Moisture may be introduced to the tobacco during treatment in the form of water or steam. This may be sprayed onto the tobacco material whilst it is being intermittently contacted with a heated surface.

In some embodiments, this introduction of moisture increases the moisture content of the tobacco material by 2% to 5% OV. In some embodiments, the moisture is introduced at different points or positions throughout the process.

As this moisturizing of the tobacco is occurring during the treatment step, the moisture content will be reduced again as the moisturized tobacco contacts the heated surface. The method may include multiple additions of moisture, so that the moisture content of the tobacco material fluctuates up and down repeatedly during the treatment.

In some embodiments, this step involves repeatedly and intermittently contacting tobacco material with one or more heated surfaces over a treatment period of from at least about 1 minute to about 15 minutes. In some embodiments, the period for which the tobacco is intermittently contacted with the heated surface is at least about 1 minute, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or at least about 14 minutes. In some embodiments, the period for which the tobacco is intermittently contacted with the heated surface is up to about 14 minutes, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, or up to about 2 minutes. In some embodiments, the tobacco material is contacted with the heated surface for a total period of from at least about 2 minutes to about 10 minutes, or from at least about 2.5 minutes to about 5 minutes.

In some embodiments, the intermittent contact may involve the tobacco being in direct and continuous contact with a heated surface for a period of up to about 5 seconds. In some embodiments, the average length of the period(s) of direct and continuous contact is from about 0.1 seconds to about 3 seconds.

Reference herein to intermittent contact of the tobacco material with the heated surface means that any part of the tobacco material is only temporarily in direct contact with the heated surface. In some embodiments, this means that the tobacco material is moved relative to the heated surface, to prevent the tobacco material coming to rest in a particular position in contact with the heated surface for too long, and/or ensuring that the same part of the tobacco material does not remain in direct contact with the heated surface for too long. Extended contact of the same part of the tobacco material with the heated surface will lead to burning which will have a detrimental effect on the physical and chemical properties of the tobacco material and will render the treated material less suitable for further use, for example in a tobacco industry product.

In some embodiments, the step of intermittently contacting the tobacco with a heated surface includes agitating the tobacco material as it is treated. In some embodiments, an apparatus is provided which includes a means for agitating the tobacco material.

In some embodiments, it is preferred that the tobacco material is agitated by tumbling the tobacco material. This may, for example, be achieved by picking up the tobacco material being treated, lifting it and then allowing it to fall, creating a tumbling movement of the tobacco material.

In some embodiments, the movement of the tobacco material may be created by a mechanism such as one comprising one or more screws. In such an arrangement, the screw includes a helical surface encircling a shaft, which is rotated, wherein the helical surface is configured to pick up tobacco material. As the shaft rotates, the helical surface scoops up at least a portion of the tobacco material being treated. This tobacco material is then carried and lifted by the rotating helical surface until the rotation of the screw allows it to fall (under gravity) away from the screw. In some embodiments, the screw or screws may be positioned to move tobacco material through a treatment chamber, as well as to agitate the tobacco material. Such an arrangement allows tobacco to be treated in a continuous manner. In some embodiments, the helical surface and/or the shaft of the screw may be heated to provide the heated surface used to treat the tobacco. Where two screws are used to move the tobacco material, these screws may be positioned in parallel, are positioned to contact, and move all of the tobacco to be treated. In some embodiments, the screw may include additional paddles to assist the picking up and carrying of the tobacco material. These paddles may also be heated surfaces used to treat the tobacco material.

In other embodiments, the tobacco material may be agitated in a rotating drum. The inside of the drum may be the chamber within which the tobacco is treated. The tobacco lies inside the drum and may be picked up from the bottom of the drum and lifted as the drum rotates. The picking up of the tobacco material may be facilitated by the drum having an inner surface which is capable of maintaining contact with the tobacco material, for example by virtue of having a rough surface or protrusions, such as paddles, which scoop up the tobacco material. As the drum rotates, the tobacco in contact with the drum's inner surface is lifted until the rotation of the drum allows it to fall (under gravity) away from the drum wall and back to the bottom of the drum. This can create a tumbling and mixing of the tobacco material. The irregularities on the inner surface of the drum may help to control how long the tobacco material remains in contact with the drum wall. The irregularities may also be used to ensure that the tobacco material does not remain in contact with the drum wall as it falls (sliding back down the wall), thereby enhancing the tumbling movement of the tobacco material. The speed of rotation will also affect the tumbling motion, as will the orientation of the axis of rotation. In some embodiments, the inner surface of the drum may be the heated surface used to treat the tobacco. The drum may rotate about a horizontal or substantially horizontal axis. In other embodiments, rotation about an inclined axis may allow the tobacco to maintain contact with the drum inner surface for longer and will also move the tobacco in a longitudinal direction. Longitudinal movement of the tobacco as a result of the rotation of the drum may additionally or alternatively be achieved by having appropriately positioned and/or angled protrusions on the inner surface of the drum.

In other embodiments, the tobacco material may be agitated by airflow. For example, tobacco material is picked up and moved by airflow.

In some embodiments, the tobacco material is not agitated by the flow of air through the device. In some embodiments, the apparatus for treating tobacco material does not include means for pumping of air through the apparatus to agitate the tobacco material.

In some embodiments, the step of intermittently contacting the tobacco with a heated surface is part of a continuous process. For example, tobacco-starting material is continuously fed into the apparatus, is treated and then leaves the apparatus as treated tobacco material. In alternative embodiments, the method is a batch process, in which a batch of tobacco starting material is fed into the apparatus, processed to produce a batch of treated tobacco material, which is removed before a new batch is processed.

Additional Treatment Steps

In some embodiments, after the combining, cutting, expansion and intermittent contact with a heated surface, the treated tobacco may be conditioned. For example, in some embodiments, moisture may be added to the treated tobacco material. In some embodiments, this is achieved by exposing the treated tobacco material to water and/or steam. In some embodiments, the moisture content is increased to above about 10% OV, or from about 10 to about 20% OV.

In some embodiments, after treatment, the treated tobacco may be cooled. In some embodiments, this may involve the use of a cooling belt, where ambient air or cooled air is passing through a layer of processed tobacco. In other embodiments, the tobacco may be cooled by any one or more of the following steps: resting, passing through a cooling cylinder, air lifting, and cooling via fluidized bed, etc.

The flow chart shown in FIG. 1 summarizes exemplary processes for treating tobacco material. The tobacco starting material may optionally have undergone pre-treatment, such as the conventional primary manufacturing (PMD) processes. For the stem, this may include, for example, one or more of: conditioning of raw stem, subsequent rolling, drying and mixing. In some embodiments, the pre-treatment of lamina may include slicing, conditioning, casing (optional), cutting, drying, cooling and mixing.

The optionally pre-treated stem is cut and/or expanded. The cutting and/or expansion may be carried out using conventional processes and apparatus, as discussed herein.

Next, the cut and/or expanded stem is combined with the lamina. This combination step may include some mixing or blending, to achieve a partially homogenized mixture of the materials before the further processing steps.

The combination of the stem and lamina is then cut. This may again be done using conventional processes and apparatus.

The cut combination of stem and lamina is then expanded. The expansion may be achieved using one or more conventional expansion processes and apparatus.

The expanded material is then fed into a treatment apparatus where it is treated by intermittent contact with a heated surface. During the treatment, the tobacco material may be agitated to create the intermittent contact with the heated surface.

Once the treatment of the tobacco material by intermittent contact with the heated surface has been completed, the treated tobacco material may optionally undergo conditioning. According to one possible embodiment, this conditioning involves adding water or steam to the treated tobacco material to increase its moisture content to in the region of 14.5% OV, for example.

The process parameters are sufficiently gentle for the treated tobacco material to maintain some or all of its physical properties. For example, the tobacco material remains sufficiently intact following treatment to allow handling and/or processing for incorporation into a tobacco-containing product, such as a smoking article. This enables the treated tobacco material to undergo handling in accordance with standard processes, in the same manner as conventional tobacco, which has not undergone the processing as described herein.

Apparatus

A specific illustrative example of an apparatus suitable for carrying out the step of intermittently contacting with a heated surface the tobacco material being treated by the methods described herein is shown in FIG. 2 . In this embodiment, the apparatus 1 includes two screws 2 in a dual screw arrangement. It is believed that this arrangement means that any part of the tobacco material may only be in contact with the heated surface for a period in the order of seconds at any one time as a result of the agitation or turbulence generated by the screws in the apparatus.

The tobacco material 8 is treated in the apparatus 1 including conveying screws 2 which include a helical surface 3 and shaft 4, wherein the screws 2 move the tobacco material through the treatment chamber 7 of the apparatus 1. The screws 2 are rotated and the shafts 4 of the screws 2 are rotated by a drive mechanism 11, including a motor.

The combination of stem and lamina, which, in some embodiments has been combined, cut and expanded, enters the treatment chamber 7 via the tobacco inlet 5, whereupon the rotating screws pick up the tobacco material, tumbling it and moving it through the treatment chamber towards the tobacco outlet 6.

More specifically, a mass of tobacco material 8 enters the treatment chamber 7 through the tobacco inlet 5. As the screw 2 rotates, the tobacco material is picked up, with some of the tobacco material coming into direct contact with the helical surface 3 and possibly also the shaft 4 of the screw 2. The tobacco material is dragged along, lifted and dropped by the screw 2, so that it is both conveyed through the treatment chamber 7 and tumbled. Tobacco which has been lifted as a result of the rotating screw(s) subsequently falls into the mass of tobacco material 8 being conveyed through the chamber 7, and the mass is constantly being mixed and moved, resulting in different parts of the mass coming into contact with the screws 2 at different times.

In the illustrated embodiment, the surfaces of the screws 2 are heated and they contact the tobacco material intermittently, in accordance with the methods for treating the tobacco.

The screws 2 have metal surfaces, which are heated by a heating medium, which is fed into the apparatus 1 via heating medium pipes 10. In the illustrated embodiment, the heating medium is thermal oil, which is heated to a desired temperature.

Only part of the tobacco material being treated will be in direct contact with a heated surface at any one time. As the tobacco is conveyed, it will be tumbled and mixed, providing agitation or turbulence of the tobacco material and the required intermittent contact with the heated surface(s). The individual contact time is believed to be no more than a few seconds at a time. The dynamics of the tobacco flow ensures a homogenous treatment of the entire tobacco mass, induced by the shape of the screws.

In the illustrated apparatus, the treatment chamber may be divided into different temperature zones 9. These represent different sections of the screws and these may be separately heated. Therefore, the apparatus can be configured to have surfaces that are heated to varying temperatures. In some embodiments, it may be desirable to control the drying and the searing phases of the treatment by exposing the tobacco to heated surfaces having different temperatures at different points in the treatment process.

Uses of the Treated Tobacco

The treated tobacco according to the present invention may be used in a tobacco industry product. A tobacco industry product refers to any item made in, or sold by the tobacco industry, typically including a) cigarettes, cigarillos, cigars, tobacco for pipes or for roll-your-own cigarettes and other make-your-own products (whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes); b) non-smoking products incorporating tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes such as snuff, snus, hard tobacco, and heat-not-burn (HnB) products; and c) other nicotine-delivery systems such as inhalers, aerosol generation devices including e-cigarettes, lozenges and gum. This list is not intended to be exclusive, but merely illustrates a range of products, which are made and sold in the tobacco industry.

The treated tobacco material may be incorporated into a smoking article. As used herein, the term ‘smoking article’ includes smokeable products such as cigarettes, cigars and cigarillos whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn products.

The treated tobacco material may be used for roll-your-own tobacco, make-your-own products and/or pipe tobacco.

The treated tobacco material may be incorporated into a smokeless tobacco product. ‘Smokeless tobacco product’ is used herein to denote any tobacco product, which is not intended for combustion. This includes any smokeless tobacco product designed to be placed in the oral cavity of a user for a limited period of time, during which there is contact between the user's saliva and the product.

The treated tobacco material may be blended with one or more tobacco materials before being incorporated into a smoking article or smokeless tobacco product or used for roll-your-own, make-your-own products or pipe tobacco.

Example 1

Tobacco stems are conventionally processed up to the point of being cut. The cut stems have a width of 0.21 mm and have a moisture content of 33% OV.

The lamina is conventionally processed up to the point of being conditioned to have a moisture content of 24% to 26% OV. The lamina is blended and carries casing.

The cut stem and the lamina are combined and cut together to cut widths of 1 mm.

The material for the process was consisting of 60% leaf lamina and 40% of unexpanded cut stem.

Subsequently, this mixture is transferred to a conventional expansion process, which leads to an expanded, dried product with a moisture content of from 13% to 15% OV after the related drying and re-ordering.

This already expanded blend is then transferred to the so-called “searing” process where it is contacted intermittently with a heated surface.

The cut and expanded stem and lamina is used as the infeed material and is treated by the methods using an apparatus as shown in FIG. 2 .

The process can be described as exposing the particles of tobacco to hot metal surfaces for seconds, before the individual particles ‘fall’ back into the overall mass of tobacco material being treated.

The residence time of the mass of tobacco particles within the apparatus (and therefore the treatment period) is 1 to 5 minutes. The heated metal surfaces are heated by a jacket, which is heated as well as the screws, bringing the heated surfaces to the desired temperature, via synthetic oil.

The figures and parameters provided in Table 1 below reflect the individual temperatures throughout the treatment process when the heating medium (oil) temperature is set to 230° C.

TABLE 1 Parameter Value Residence time 180 seconds Set Point temperature 230° C. Jacket temperature @ exit (14) 217° C. Screw 1 temperature @ exit 221° C. Screw 2 temperature @ exit 221° C. Temperature sensor 1 126° C. Temperature sensor 2 130° C. Temperature sensor 3 154° C. Temperature sensor 4 168° C. Temperature sensor 5 175° C. Temperature sensor 6 178° C. Temperature sensor 7 145° C. Temperature sensor 8 146° C. Temperature sensor 9 161° C. Temperature sensor 10 169° C. Temperature sensor 11 176° C. Temperature sensor 12 182° C.

The tobacco is treated by processes involving residence times (or treatment periods) of around 3 minutes and a rate of throughput of tobacco material of around 35 kg/h of tobacco having 20 a moisture content of approximately 14.5% OV.

The process can be split into two different phases. Throughout the first phase, the tobacco particles are losing their moisture. At a heating medium (oil) temperature of 230° C. the tobacco particles have a moisture content of 0% OV after approximately 2 minutes. The second phase occurs for the remainder of the treatment and the effect has been termed “searing”. Throughout this second phase the main chemical changes are happening.

The searing process leads to a reduction in the nicotine content of the treated tobacco (for example, a reduction of more than 35% at a heating medium temperature of 230° C.), as well as a significant reduction in the total sugars and ammonia content of the tobacco (for example, a reduction of more than 60%).

Furthermore, the searing process also causes the tobacco material to undergo significant changes throughout processing. It has been shown that these changes translate into changes in the organoleptic properties of the processed material, which are discernible in the smoke produced when the treated tobacco is combusted, for example in a cigarette. The organoleptic properties of this smoke are described in very positive terms by expert smokers, indicating that the tobacco treatment leads to the production of the treated material with beneficial and desirable properties. This is both in terms of the reduction in some undesirable tobacco constituents, and improved organoleptic properties. These changes also manifest themselves in a darkening or browning of the color or appearance of the tobacco following the searing treatment.

What is more, as a result of the combined processing of the stem and lamina, a very high consistency of the processed material is achieved in terms of color and particle size. This may, for example, enable very consistent combustion properties in combustible products. The stem portion of the processed blend becomes literally invisible in the final material and this is desirable in a number of products, including tobacco for pipes, for roll-your-own cigarettes or make-your-own products.

Furthermore, the combination of steps results in a product with higher fill values compared with the products of conventional processing, i.e., improved tobacco volumes per mass.

The normalized fill values of the 60% lamina/40% stem mixture was measured before the searing process at 6.75 ml/g and resulted into a normalized fill value after searing and the related re-ordering of 8.10 ml/g.

Example 2

This process is similar to the process used in Example 1, but with already expanded stem as the infeed material to be combined with the leaf lamina prior to combined cutting.

The material for the process was consisting of 60% leaf lamina and 40% of expanded cut stem.

This expanded stem has a moisture content of from 22% to 24% OV.

The cut stem and the lamina are combined and cut together to a cut width of 0.9 mm.

Subsequently, this mixture is transferred to a conventional expansion process, which leads to an expanded product with a moisture content of from 14% to 15% OV after the related drying and re-ordering.

The figures and parameters provided in Table 2 below reflect the individual temperatures throughout the treatment process when the heating medium (oil) temperature is set to 230° C. as in example 1.

TABLE 2 Parameter Value Residence time 180 seconds Set Point temperature 230° C. Jacket temperature @ exit (14) 217° C. Screw 1 temperature @ exit 221° C. Screw 2 temperature @ exit 221° C. Temperature sensor 1 128° C. Temperature sensor 2 133° C. Temperature sensor 3 155° C. Temperature sensor 4 171° C. Temperature sensor 5 176° C. Temperature sensor 6 181° C. Temperature sensor 7 148° C. Temperature sensor 8 150° C. Temperature sensor 9 162° C. Temperature sensor 10 171° C. Temperature sensor 11 178° C. Temperature sensor 12 184° C.

The tobacco is treated by processes involving residence times (or treatment periods) of around 3 minutes and a rate of throughput of tobacco material of around 30 kg/h of tobacco having a moisture content of approximately 14.5% OV.

The searing process leads to a reduction in the nicotine content of the treated tobacco (for example, a reduction of more than 40% at a heating medium temperature of 230° C.), as well as a significant reduction in the total sugars and ammonia content of the tobacco (for example, a reduction of more than 70%).

The normalized fill values of the 60% lamina/40% stem mixture was measured before the searing process at 7.95 ml/g and resulted into a normalized fill value after searing and the related re-ordering of 9.60 ml/g.

In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which the claimed inventions may be practiced and provide for superior methods, apparatus and treated tobacco materials and extracts therefrom. The advantages and features of the disclosure are of a representative sample of embodiments only and are not exhaustive and/or exclusive. They are presented only to assist in understanding and teach the claimed features. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilized and modifications may be made without departing from the scope and/or spirit of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. In addition, the disclosure includes other inventions not presently claimed, but which may be claimed in future. 

1. A method of treating tobacco material comprising: combining pre-cut and/or pre-expanded stem with lamina to form an initial combination of stem and lamina; cutting the initial combination of stem and lamina; expanding the combination of stem and lamina; and intermittently contacting the expanded combination of stem and lamina with a heated surface to produce a treated tobacco material.
 2. A method as claimed in claim 1, wherein the initial combination of stem and lamina comprises from at least about 5% lamina up to about 99% lamina, by weight, and/or from at least about 1% stem up to about 95% stem, by weight.
 3. A method as claimed in claim 1, wherein the expanded combination of stem and lamina is agitated so that it is intermittently in contact with the heated surface.
 4. A method as claimed in claim 1, wherein the heated surface has a temperature of from at least about 100° C. to about 300° C. prior to contact with the tobacco material.
 5. A method as claimed in claim 4, wherein the heated surface has a temperature of from at least about 120° C. to about 250° C. prior to contact with the tobacco material, or from at least about 150° C. to about 300° C. prior to contact with the tobacco material.
 6. A method as claimed in claim 1, wherein contacting the expanded combination of stem and lamina with the heated surface heats the tobacco material to a peak temperature of from about 120° C. to about 230° C.
 7. A method as claimed in claim 1, wherein the heated surface is a heated metal surface.
 8. A method as claimed in claim 1, wherein the treated tobacco material has a moisture content from 0 to about 10% oven volatiles (OV),
 9. A method as claimed in claim 1, wherein the expanded combination of stem and lamina has a moisture content of at least 5% OV before it is intermittently contacted with a heated surface.
 10. A method as claimed in claim 9, wherein the expanded combination of stem and lamina has a moisture content of from about 5% to about 25% OV before it is intermittently contacted with a heated surface, or from about 12 to about 16% OV.
 11. A method as claimed in claim 1, wherein the expanded combination of stem and lamina is intermittently contacted with a heated surface for a period of from at least about 1 minute to about 15 minutes.
 12. A method as claimed in claim 11, wherein the expanded combination of stem and lamina is intermittently contacted with a heated surface for a period of from at least about 2 minutes to about 10 minutes.
 13. A method as claimed in claim 12, wherein the expanded combination of stem and lamina is intermittently contacted with a heated surface for a period of from at least about two and a half minutes to about 5 minutes.
 14. A method as claimed in claim 1, wherein at least one of water and steam is added to the expanded combination of stem and lamina whilst it is intermittently contacted with a heated surface, to increase its moisture content.
 15. A method as claimed in claim 14, wherein at least one of water and steam is repeatedly added to the expanded combination of stem and lamina whilst it is intermittently contacted with a heated surface, to increase its moisture content.
 16. A method as claimed in claim 1, wherein the method is a continuous process.
 17. A method as claimed in claim 1, wherein the expanded combination of stem and lamina is agitated by at least one of the group consisting of: a screw mechanism; a dual screw mechanism; air flow; and a rotating drum.
 18. A method as claimed in claim 1, wherein the fill value of the treated tobacco is at least about 5% or at least about 15% greater than the fill value of the combination of stem and lamina immediately prior to the step of intermittently contacting the expanded combination of stem and lamina with a heated surface.
 19. A method as claimed in claim 18, wherein the fill value of the treated tobacco is from about 30% to about 50% greater than the fill value of the initial combination of stem and lamina.
 20. A method as claimed in claim 1, wherein the sugar content of the treated tobacco is from about 20% to about 95% less than the sugar content of the initial combination of stem and lamina.
 21. A method as claimed in claim 20, wherein the sugar content of the treated tobacco is from about 60% to about 90% less than the sugar content of the initial combination of stem and lamina.
 22. A method as claimed in claim 1, wherein the nicotine content of the treated tobacco is from about 10% to about 80% less that the nicotine content of the initial combination of stem and lamina.
 23. A method as claimed in claim 22, wherein the nicotine content of the treated tobacco is from about 35% to about 70% less that the nicotine content of the initial combination of stem and lamina.
 24. A method as claimed in claim 1, wherein the ammonia content of the treated tobacco is from about 30% to about 99% less that the ammonia content of the initial combination of stem and lamina.
 25. A method as claimed in claim 24, wherein the ammonia content of the treated tobacco is from about 50% to about 90% less that the ammonia content of the initial combination of stem and lamina.
 26. A method as claimed in claim 1, wherein the cut combination of stem and lamina is expanded by exposing the cut stem and lamina to an expansion agent.
 27. A method as claimed in claim 26, wherein the expansion agent is selected from the group consisting of: liquid carbon dioxide, solid carbon dioxide, steam, liquid nitrogen, liquid short (C5 or C6) chain carbohydrates, or mixtures thereof.
 28. An apparatus for carrying out the method of claim 1, comprising a module for intermittently contacting the expanded combination of stem and lamina with a heated surface, the module comprising a heated surface provided to intermittently contact the expanded combination of stem and lamina.
 29. An apparatus as claimed in claim 28, further comprising a means for agitating the expanded combination of stem and lamina.
 30. An apparatus as claimed in claim 29, wherein the means for agitating the expanded combination of stem and lamina comprises at least one of the group consisting of: a screw mechanism; a dual screw mechanism; air flow; and a rotating drum.
 31. An apparatus as claimed in claim 28, wherein the heated surface has a temperature of from at least about 100° C. to about 300° C. prior to contact with the tobacco material.
 32. An apparatus as claimed in claim 31, wherein the heated surface has a temperature of from at least about 120° C. to about 250° C. prior to contact with the expanded combination of stem and lamina, or from at least about 150° C. to about 300° C. prior to contact with the expanded combination of stem and lamina.
 33. An apparatus as claimed in of claim 28, wherein contacting the expanded combination of stem and lamina with the heated surface heats the expanded combination of stem and lamina to a peak temperature of from about 120° C. to about 230° C.
 34. An apparatus as claimed in claim 28, wherein the heated surface is a heated metal surface.
 35. An apparatus as claimed in claim 28, wherein the heated surface is heated by a heating medium, the heating medium being water, oil, steam, electricity, or combinations thereof.
 36. A treated tobacco material, which is obtained or obtainable by a method as claimed in claim
 1. 37. A treated tobacco material as claimed in claim 36, wherein the treated tobacco material has reduced levels of one or more of the group consisting of: sugars, nicotine and ammonia, compared to level in the initial combination of stem and lamina.
 38. A treated tobacco material as claimed in claim 37, wherein the sugar content of the treated tobacco is from about 20% to about 95%, or from about 60% to about 90%, less than the sugar content of the initial combination of stem and lamina.
 39. A treated tobacco material as claimed in claim 37, wherein the nicotine content of the treated tobacco material is from about 10% to about 80%, or from about 35% to about 70%, less than the nicotine content of the initial combination of stem and lamina.
 40. A treated tobacco material as claimed in claim 37, wherein the ammonia content of the treated tobacco material is from about 30% to about 99%, or from about 50% to about 90%, less than the ammonia content of the initial combination of stem and lamina.
 41. A treated tobacco material as claimed in claim 36, wherein the fill value of the treated tobacco is at least about 25% or at least about 30% greater than the fill value of the initial combination of stem and lamina.
 42. A treated tobacco material as claimed in claim 41, wherein the fill value of the treated tobacco is from about 30% to about 50% than the fill value of the initial combination of stem and lamina.
 43. A tobacco industry product comprising the treated tobacco material of claim
 36. 44. Use of the treated tobacco material of claim 36 for the manufacture of a tobacco industry product. 